The invention relates to a wind turbine blade, wind turbine and a method for manufacturing a wind turbine blade.
Modern wind turbine blades hold different apparatuses in order to survey and protect the blades from overload and damage such as sensor means. The sensor means are usually externally supplied with electrical power via electrical cables running through the interior of the blade.
Wind turbine blades may also comprise a lightning protection system which usually includes a number of lightning receptors, e.g., on the blade tip surface and with connections to a lightning down conductor. The lightning down conductor runs through the interior of the blade and via other parts of the wind turbine to a ground potential.
A problem with the use of internal electrical cables for sensors and a lightning protection system in the wind turbine blade is the risk of lightning current following the electrical cables to a ground potential instead of the down conductor after a lightning flashover.
Even if a flashover does not occur when the lightning strikes the wind turbine blade, another problem may arise by the electromagnetic interference between the lightning down conductor and the sensor systems.
The result of the abovementioned lightning situations may be time consuming and costly repair of the sensor systems.
The object of the invention is to establish a wind turbine blade having electrically powered means having less vulnerability to lightning strikes on the blade.